!!! Overview
[{$pagename}] is an [HTTP Header Field] which indicates the [authentication] [scheme(s)|Authentication Method] and parameters applicable to the target resource.

     WWW-Authenticate = 1#challenge

A server generating a 401 (Unauthorized) response MUST send a [{$pagename}] [HTTP Header Field] containing at least one challenge.  A server MAY generate a [{$pagename}] [HTTP Header Field] in other response messages to indicate that supplying [credentials] (or different [credentials]) might affect the response.

A proxy forwarding a response __MUST__ __NOT__ modify any [{$pagename}] fields in that response.

User agents are advised to take special care in parsing the field value, as it might contain more than one challenge, and each challenge can contain a comma-separated list of [authentication] parameters.  Furthermore, the [HTTP Header Field] itself can occur multiple times.

!! More Information
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[{ReferringPagesPlugin before='*' after='\n' }]